What depth of investigation can be achieved with the Stratagem?

The Stratagem is a frequency domain instrument using the technique known as hybrid-source AMT (audio magnetotellurics). It uses a combination of natural telluric currents in the ground and signals from a controlled-source transmitter. The range of depth is determined by the frequencies available and by the apparent resistivity of the sounding site. The lower the frequency is the greater the depth of investigation, and the higher the resistivity the greater the depth. The frequency bandwidth of the Stratagem receiver is 10 Hz to approximately 70 kHz. At 10 Hz in 10 Ohm-meter earth the depth of investigation is approximately 350 meters. At 10 Hz in 100 Ohm-m earth the depth is approximately 1,100 meters.

"...we want to express our most sincere gratitude to Geometrics, Inc. personnel for the efficient support they gave us regarding the operation of some of their products that were used last June during the sea campaign of one of our projects in Punta Zempoa"